(a) Field of the Invention
The present invention relates to a manual transmission and a shift lug structure thereof. In more particular aspects, the present invention relates to a manual transmission and a shift lug structure thereof where a direct shifting from a first speed to a reverse speed can be possible.
(b) Description of the Related Art
Nowadays, as performance of vehicles is improved, a transmission that generates more power has been developed. However, as a transmission generates more power, problems may occur such that a capacity of a synchronizer needs to be increased.
As shown in FIG. 8, a conventional manual transmission includes a main shaft 100, a hub 110, a gear assembly 120, and a synchronizer sleeve 170.
The main shaft 100 is connected to an engine and receives a power.
The hub 110 is coupled to an exterior circumference of the main shaft 100.
The gear assembly 120 includes a first speed clutch gear 130, a second speed clutch gear 140, synchronizer cones 150, and synchronizer rings 160. The first and second speed clutch gears 130 and 140 are disposed respectively on both sides of the hub 110. The synchronizer cones 150 are fixed to the first and second speed clutch gears 130 and 140. The synchronizer rings 160 apply a frictional force to the synchronizer cones 150 and synchronize the gear assembly 120 with the main shaft 100.
The synchronizer sleeve 170 is slidably connected to an exterior circumference of the hub 110, and connects the main shaft 100 with the gear assembly 120.
The shifting process according to the conventional manual transmission will hereinafter be described in detail, referring to FIG. 9.
When a driver controls a shift lever, a shift control lever and a select control lever of the transmission are operated by a shift cable. In this case, a shift fork fixedly connected to the synchronizer sleeve 170 moves the synchronizer sleeve 170 to the left or the right according to an operation of the shift control lever and the select control lever.
Therefore, in a neutral state, the synchronizer sleeve 170 moves and contacts with the synchronizer rings 160, and the synchronizer rings 160 apply the frictional force to the synchronizer cones 150 fixed to the first and second speed clutch gears 130 and 140 so as to rotate the synchronizer cones 150.
After that, the synchronizer sleeve 170 is engaged with the first speed clutch gear 130 or the second speed clutch gear 140, and synchronizes the main shaft 100 with the first speed clutch gear 130 or the second speed clutch gear 140.
According to the conventional manual transmission, an inertia moment of the transmission increases in proportion to a square radius thereof. However the capacity of the synchronizer increases in proportion to a radius thereof. Therefore, it can be difficult to increase the capacity of the synchronizer in proportion to an increase of the capacity of the transmission.
In addition, if the capacity of the synchronizer is low, a shift feel of the transmission may deteriorate, and a clash and a shift shock may occur.
Meanwhile, a sliding-type apparatus or a synchro-type apparatus for preventing a reverse noise is used so as to prevent the reverse noise in a process of shifting to the reverse shift speed. However, in this case, the transmission may be long.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.